Integrated Touch Display Electrode Grouping for Voltage Symmetry
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Solution Overview
Problem
Display devices with integrated touch screens experience issues such as block dim and flickering due to voltage differences between electrodes in display and touch driving modes, causing shifts in grayscale levels and asymmetric voltage formations.
Innovation Solution
A display device with electrodes divided into multiple groups, where a display driver IC applies a common voltage in display mode and selectively applies a touch scan signal or common voltage in touch mode, using a touch IC to generate the touch scan signal and manage voltage distribution across groups.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a common voltage is applied to electrodes in display driving mode and ground-level voltage is applied in touch driving mode, then the touch sensing function is enabled, but voltage differences cause block dim and grayscale level shifts
Solution Approach 1:
The electrodes are divided into multiple groups (first group and second group) that can be independently controlled. This segmentation allows different voltage signals to be applied to different groups, enabling the display driver IC to manage voltage distribution separately for each group and prevent block dim caused by voltage differences.
Solution Approach 2:
The patent implements dynamic voltage switching where the display driver IC selectively applies either common voltage or ground-level voltage to electrode groups based on the current driving mode (display mode or touch mode). This dynamic adaptation allows the system to maintain display stability while enabling touch sensing functionality.
2Adaptability or versatility
If voltage levels are changed between display and touch modes, then touch driving is enabled, but grayscale levels shift and flicker occurs
Solution Approach 1:
The patent applies preliminary compensation by pre-adjusting voltage levels for each electrode group before mode switching occurs. The display driver IC prepares the voltage signals in advance to ensure that when switching between display and touch modes, the grayscale levels remain consistent and flicker is prevented.
Solution Approach 2:
The system implements feedback control where the display driver IC continuously monitors the voltage applied to each electrode group and adjusts the signals to maintain consistent grayscale levels across mode transitions, preventing flicker and maintaining display quality.
3Adaptability or versatility
If electrodes serve dual functions as common electrodes and touch electrodes, then integration is achieved, but asymmetric voltage formation increases flicker
Solution Approach 1:
By dividing electrodes into separate groups, the patent enables each group to be independently configured for its current function. This segmentation allows the system to maintain symmetric voltage formation for common electrode operation while enabling touch electrode functionality, resolving the conflict between multi-functionality and voltage symmetry.
Solution Approach 2:
The patent applies different voltage characteristics to different electrode groups based on their local requirements. The display driver IC determines which group needs common voltage characteristics and which needs touch sensing characteristics, allowing each local region to have optimized voltage properties that maintain overall system reliability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution prevents block dim and flickering by maintaining consistent voltage levels across electrodes, ensuring symmetric voltage formations with respect to ground-level voltage, thereby enhancing touch sensitivity and display stability.
Implementation Method 1
each of the touch ICs 30a and 30b includes touch IC channels respectively corresponding to the lines 13 for self-capacitive touch sensing
Data Source
AI summary
A display device with an integrated touch screen including a panel including electrodes divided into n number of groups, where n is an integer more than or equal to two; a display driver IC configured to apply a common voltage to the n divided groups when a driving mode of the panel is a display driving mode, and to selectively apply a touch scan signal or the common voltage to the n divided groups when the driving mode of the panel is a touch driving mode; and a touch IC configured to generate the touch scan signal to apply the touch scan signal to the display driver IC.